LBC Microscopy

Comparison with conventional Pap smear

Smear pattern

Conventional Pap smears (CP) may be unevenly distributed across the slide with areas of thicker and thinner cellular material, often trapped within mucus. In LBC smears cellular distribution is regular. ThinPrep®(TP) slides present cells largely within a single focal plane; SurePathTM (SP) smears exhibit slightly greater overlapping of cellular material.

Conventional Pap

Cellular material is trapped within mucus and unevenly distributed

SurePath™

Cellular material is distributed evenly with some overlapping

ThinPrep®

Cellular material is distributed evenly with minimal overlapping

Preservation and cellular features

Immediate fixation of LBC samples improves preservation of cellular morphology and reduces air-drying and crush artefacts compared with CP. Cellular components such as cell membranes and chromatin may appear more sharply defined in LBC preparations than in CP as a result of improved cell preservation. Cell sizes appear slightly smaller in LBC preparations than in CP, however overall cellular morphology is unchanged. Tissue architecture in larger cell groups may be better appreciated in CP compared with LBC, however small cellular clusters and tissue fragments are still preserved.

Conventional Pap

Air-drying and inadequate fixation is more common in CP smears than in LBC preparations which may make accurate interpretation difficult

ThinPrep® - Squamous Metaplasia

Cytoplasmic and nuclear features in metaplastic cells are well-preserved in this TPpreparation

SurePath™ - Repair

Cytoplasmic and nuclear features are well-preserved in this SP preparation which shows reparative changes

Smear Background

The background in LBC slides is cleaner than in CP. Mucus is removed or reduced, red blood cells are haemolysed and excess blood and inflammatory cells are also removed or substantially reduced compared with CP. Necrotic debris and tumour diathesis are visible in LBC preparations but may be less prominent than in CP.

Conventional Pap - Blood and Leucocytes

Blood cells and leucocytes in CP smears may obscure cellular material

ThinPrep® - Inflammation

Inflammatory cells are present and identifiable however other cellular elements are not obscured

SurePath™ - Inflammation

Although inflammatory cells are present they do not obscure other cellular elements